JPS6331501B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a curable composition that is cross-linked and cured by ultraviolet rays or light to produce a cured resin product having excellent heat resistance, hardness, flexibility, etc. In recent years, social demands such as resource conservation, energy conservation, and non-pollution have increased, and it has become urgent to respond to these demands. In response to this, for example, solvent-free coatings and efficient curing methods are being studied for coatings used as electrical insulating materials. In response to such demands, the present inventors conducted research in search of a curable composition capable of obtaining a resin-like cured product with excellent curability, hardness, flexibility, etc. without using a solvent.
This led to the present invention. The present invention is based on the following general formula: A(OH) _n () (A in the formula is a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid or a derivative thereof;
Contains 10 mol% or more of a trivalent or higher polyol based on the dicarboxylic acid component, is synthesized from a polyol component mainly composed of an aliphatic polyol, and the excess amount of the polyol component with respect to the dicarboxylic acid component is 35 mol% or less is the m-valent residue of the ester oligomer, where m is determined by the ratio of the number of trivalent or higher polyol residues and the total number of polyol residues to the number of carboxylic acid residues in the ester oligomer. The above indicates a number less than or equal to 23. ) and (b) the following general formula: 1 mole of imidocarboxylic acid represented by (n in the formula is an integer of 1 or 2) (where 1 is 2
The above indicates the number satisfying m/2lm); or the following general formula: 3,6-endomethylene-1,
1 mol of 2,3,6-tetrahydro-cis-phthalic anhydride (where l is the same as above) and the following general formula: NH ₂ (CH ₂ ) _o COOH () (wherein n indicates the same as above)
This is a method for producing a composition curable by ultraviolet rays or heat, characterized by reacting 1 mol of an aminocarboxylic acid represented by (where 1 is the same as above). The reaction in the present invention can be represented by the following Reaction Formula 1 or 2. (However, A, l, m, and n in the formula are the same as those mentioned above.) The composition obtained by the method of the present invention is a solid resinous substance at room temperature, and at a temperature of 80°C or higher. Softens by heating, usually at a temperature of 80 to 140 degrees Celsius
It becomes a viscous liquid with a viscosity of around 5000 centipoise (cP), and can be molded at temperatures within this range. Further, the composition of the present invention is cured by heat or ultraviolet rays to produce a cured product with excellent heat resistance, hardness, flexibility, etc. That is, the composition obtained by the method of the present invention can be heat-treated at a temperature in the range of 200 to 450°C, or can be irradiated with ultraviolet rays using a high-pressure mercury lamp, ultra-high-pressure mercury lamp, xenon lamp, etc. after adding an ultraviolet sensitizer. It hardens to produce a cured product that normally does not soften at temperatures below 250°C. When thermally curing the composition obtained by the method of the present invention, conditions of 250 to 450°C are desirable in consideration of shortening the time required for curing and uniformity of the cured product. Further, the degree of curing of the composition obtained by the method of the present invention can be determined by the ratio of insoluble residue, ie, the gel fraction, when the cured product is treated in m-cresol at 90° C. for 5 hours. According to this determination method, the cured product of the composition obtained by the method of the present invention exhibits excellent properties when the gel fraction is 90% or more.
In the case of heat curing, the curing conditions that result in 90% or more are
For example, in the case of UV curing at 250℃ for about 8 minutes,
When irradiating from a distance of 5 cm using a high-pressure mercury lamp with an input density of 80 W/cm, it takes about 1.5 seconds. The oligoester compound constituting the base resin component in the composition obtained by the method of the present invention is
(1) a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid or a derivative thereof, and (2) a trivalent polyol of 10 mol% or more based on the dicarboxylic acid component, and mainly composed of an aliphatic polyol. It is an ester oligomer which is synthesized from a polyol component and has a hydroxyl group at the terminal in an excess amount of the polyol component relative to the dicarboxylic acid component of 35 mol % or less. Examples of aromatic dicarboxylic acids or derivatives thereof constituting the dicarboxylic acid component of this ester oligomer include terephthalic acid, isophthalic acid, lower alkyl esters thereof such as methyl esters and ethyl esters, and acid halides such as acid chlorides. etc. These aromatic dicarboxylic acids or derivatives thereof can be used alone or as a mixture in any proportion. Furthermore, non-aromatic dicarboxylic acids such as aliphatic dicarboxylic acids or derivatives thereof can be added as the dicarboxylic acid component. Examples of non-aromatic carboxylic acids include aliphatic carboxylic acids such as succinic acid, adipic acid, sebacic acid, and the above-mentioned derivatives thereof. The amount of these non-aromatic dicarboxylic acids or derivatives thereof is desirably 20 mol% or less of the total dicarboxylic acid components from the viewpoint of heat resistance of the cured product obtained from the composition produced by the method of the present invention. . Examples of aliphatic polyols constituting the polyol component of the ester oligomer include bifunctional alcohols such as ethylene glycol and propylene glycol, trifunctional alcohols such as trimethylolpropane and glycerin, and 4-functional alcohols such as pentaerythritol.
There are functional alcohols and the like, and these aliphatic polyols can be used alone or as a mixture. Also, non-aliphatic polyols such as bisphenol A, hydrogenated bisphenol A, trishydroxyethyl cyanurate, etc. can be added to a part of the polyol component. The reason for limiting the content of trivalent or higher polyol in the polyol component is that if this amount is less than 10 mol%, the cured product obtained from the curable composition using an ester oligomer as a base resin may not be suitable depending on the application. This is because problems such as insufficient hardness or slow curing speed occur. The reason for limiting the excess amount of the polyol component to the dicarboxylic acid component in the above ester oligomer to 35 mol% or less is that this excess amount is 35 mol% or less.
This is because a curable composition obtained using an ester oligomer exceeding the above as a base resin is undesirable because the cured product has insufficient heat resistance and flexibility. Also, the most desirable ester oligomer constituting the base resin component of the composition obtained by the method of the present invention is a dicarboxylic acid component containing 20 mol% or less of isophthalic acid or adipic acid or a derivative thereof and 80 mol% or more of the dicarboxylic acid component. It is synthesized using a mixture of terephthalic acid or its derivatives and a mixture of trimethylolpropane and/or glycerin and ethylene glycol as polyol components, and the number of trifunctional polyol residues is equal to the number of dicarboxylic acid residues. The ester oligomer is 20 to 60%, and the excess amount of the polyol component to the dicarboxylic acid component is 35 mol% or less. Moreover, the imidocarboxylic acid represented by the formula () is a combination of 3,6-endomethylene-1,2,3,6-tetrahydro-cis-phthalic anhydride (hereinafter abbreviated as nadzic acid) and glycine or β-alanine. Obtained by heating to 140°C in a small amount of a solvent such as xylene, stirring, and removing the water produced.
Although it can be confirmed by infrared absorption spectrum and elemental analysis that this compound has the structure of formula (), the method for producing this compound is not limited to this method. Also, in place of the imidocarboxylic acid represented by the formula (), an equimolar mixture of nadzic acid anhydride represented by the formula () and an aminocarboxylic acid represented by the formula () is used to form an ester oligomer represented by the formula (). Even if the reaction is carried out, the composition obtained is exactly the same as when using the imidocarboxylic acid represented by the formula (), and this can be confirmed by the infrared absorption spectrum. The aminocarboxylic acid represented by the formula ( ) is glycine when n=1, and β-alanine when n=2. In the composition obtained by the method of the present invention, imidocarboxylic acid (formula) or nadic anhydride (
The amount of an equimolar mixture of ester oligomer (formula) and aminocarboxylic acid (formula) is 1 mol per 1 mol of ester oligomer (formula) (where 1 is 2 or more, m/2 liter).
The reason why the curing of the composition does not proceed sufficiently is below this limited range, and if this limited range is exceeded, the imidocarboxylic acid (formula) This is because the particles remain inside the cured product and adversely affect the flexibility and other properties of the cured product. In a preferred embodiment of the method of the invention, a small amount of polymerization inhibitor is added to an equimolar mixture of an oligoester compound (formula) and the desired amount of imidocarboxylic acid (formula) or nadzic anhydride (formula) and aminocarboxylic acid (formula). A curable composition is produced by adding a dehydration agent and a dehydration catalyst and heating the resulting water, which is taken out of the system as an azeotrope with a solvent such as xylene or naphtha, and the solvent is taken out. In this reaction, the completion of the reaction can be confirmed by the amount of distilled water. As catalysts that can be used in the method of the present invention, organic titanates such as tetrabutoxytitanium and tetraisopropoxytitanium, and acid catalysts such as p-toluenesulfonic acid and dimethylbenzenesulfonic acid can be used. The amount of these catalysts used is preferably 0.2 to 2% by weight based on the raw material. Hydroquinone is also used as a polymerization inhibitor.
Commonly used substances such as p-methoxydiphenol and N-nitrosophenylhydroxylamine can be used. The amount of these polymerization inhibitors added is preferably 0.01 to 0.5% by weight based on the raw material. This polymerization inhibitor is added for thermal stability during the reaction, but
It also maintains thermal stability during molding before curing. Therefore, there is generally no need to add further stabilizers during processing. The composition obtained by the method of the present invention is cured by ultraviolet rays or heat, and the curing method can be by using ultraviolet rays or heat alone or by a combination of both. Sensitizers for curing with ultraviolet light include benzoin ethers such as benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzophenone derivatives such as benzophenone, methyl orthobenzoyl benzoate, and disulfides such as diphenyl sulfide. etc. These sensitizers may be used alone or in combination. Furthermore, accelerators such as amines and Michler's ketone may be used to accelerate curing. The concentrations of these sensitizers are
0.1 to 5% by weight is suitable. Although the composition obtained by the method of the present invention can be put to practical use alone, it may contain vinyl monomers or polyfunctional monomers to lower the viscosity during molding, add fillers, or further increase the curing speed. It is also possible to use them in combination. Examples of such monomers include ethylene glycol bisacrylate, ethylene glycol bismethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, N -Vinylpyrrolidone, etc. The amount of these monomers to be blended is preferably 0 to 3 parts by weight per 10 parts by weight of the composition obtained by the method of the present invention in view of the properties of the cured product. The composition obtained by the method of the invention has good thermal stability and a long pot life. For example, even when heated at 180°C for 10 hours or 160°C for 50 hours, no increase in viscosity is observed, and no substantial change in the properties of the cured product is observed. Further, the cured product obtained from the composition obtained by the method of the present invention contains an imide bond,
Has heat resistance. This cured product further has mechanical properties,
It also has excellent electrical properties and excellent chemical resistance.
It exhibits solvent resistance and is ideal for applications such as solvent-free paints. For example, when the composition obtained by the method of the present invention is used as an insulating coating, the resulting cured film has better heat resistance, abrasion resistance, and chemical resistance than the film obtained when using current solvent-based varnishes. It also exhibits properties that are equivalent or better in terms of properties such as durability, thermal shock resistance, and dielectric breakdown voltage. Since the curable composition obtained by the method of the present invention has the above-mentioned properties, it can be used, for example, as a solvent-free electrical insulation paint or other paints. It is not limited to use. The present invention will be described below with reference to Examples. In the examples, all "parts" indicate parts by weight. Furthermore, the term "excess amount of polyol component" refers to the excess amount of polyol component relative to dicarboxylic acid component, that is, the excess amount of total polyol residues relative to the total number of carboxylic acid residues. Further, all percentages of the amount of polyol having a valence of 3 or more indicate mol% relative to the dicarboxylic acid component. Example 1 Synthesized from dimethyl terephthalate, dimethyl isophthalate, trimethylolpropane, and ethylene glycol, with a ratio of p-phenylene groups/m-phenylene groups of 9/1, and trimethylolpropane to the total number of dicarboxylic acid residues. number of residues is 20
%, 368 parts of ester oligomer with an excess amount of polyol component of 20%, 215 parts of N-carboxymethylnadic imide (imidocarboxylic acid where n=1 in the formula), p-methoxyphenol 0.4
1 part and 50 parts of xylene were weighed out and stirred while heating it to 140°C. After it became homogeneous, 2 parts of tetraisopropoxy titanium (hereinafter abbreviated as TPT) was dissolved in 50 parts of xylene. The solution was gradually added, and while xylene of the water-xylene mixture to be distilled out was returned to the reaction system, heating and stirring were continued until 17 parts of water had been distilled out. Next, the resulting solution was heated and stirred while blowing nitrogen into it until the internal temperature reached 160° C., and it was confirmed by weight loss that the removal of xylene was completed, that is, the reaction was completed. The thus obtained resinous substance was solid at room temperature, began to soften when heated at about 70°C, and gradually became liquid, exhibiting a viscosity of about 4000 cP at 100°C. Next, in order to evaluate the curability of this resinous material and the characteristics of the cured product, the resinous material was heated to 100°C and then applied to a copper wire with a diameter of 1mm, and a coating film was formed using a die of 1.12mmφ. and heated at 250°C for 10 minutes to obtain a cured film. As a result of measuring the gel fraction of this film using metacresol at 90°C, it was found that this resinous material was cured to a gel fraction of 96% by heat treatment at 250°C for 10 minutes. Table 1 shows the properties of this film as an insulating film. Example 2 100 parts of the resinous substance of Example 1 and 1 part of benzoinpropyl ether were weighed into a container, heated to 100°C to make a homogeneous liquid, and then placed on a copper wire with a diameter of 1 mm in the same manner as in Example 1. Two 2kw lights are applied to form a coating film and are designed to ensure that UV rays are evenly applied to each area.
The material was passed through a high-pressure mercury lamp (input density 80 W/cm) at a distance of 5 cm from the mercury lamp, and substantially each part was irradiated for 1.5 seconds to examine the ultraviolet curability and properties of the cured product. The gel fraction of the obtained cured film was measured in the same manner as in Example 1 and was 98%.
The properties of this cured film are shown in Table 1. Example 3 235 parts of an ester oligomer synthesized from dimethyl terephthalate, trimethylolpropane and ethylene glycol, with a trimethylolpropane residue of 60% relative to the total dicarboxylic acid residues and an excess of polyol component of 25%, N- 200 parts of carboxymethylnadic imide, 0.4 parts of hydroquinone,
A resinous material was obtained in the same manner as in Example 1 using 4 parts of tetrabutoxytitanium and 100 parts of xylene.
This resinous material was solid at room temperature, but when heated to 130°C, it exhibited a viscosity of approximately 2000 cP. Next, 1 part of benzoinpropyl ether was added to 100 parts of this resinous material, and after homogenization by heating to 130°C, the curability and properties of the cured film of the obtained composition were confirmed in the same manner as in Example 2. . The gel fraction of the obtained cured film was 98%, and the properties of the cured film were as shown in Table 1. Example 4 Synthesized from dimethyl terephthalate, adipic acid, glycerin and ethylene glycol, the ratio of p-phenylene groups/m-phenylene groups is 9/1, and the number of glycerin residues to the total number of dicarboxylic acid residues is 20. %, 347 parts of ester oligomer with an excess amount of polyol component of 20%, 188 parts of N-2-carboxyethylnadic imide (imidocarboxylic acid where n = 2 in the formula), 0.4 part of p-methoxyphenol, p-methoxyphenol 0.4 parts -A resinous material was obtained in the same manner as in Example 1 from 2 parts of toluenesulfonic acid and 100 parts of xylene. This resinous substance is solid at room temperature, softens when heated, and at 120°C it becomes approximately
It became a liquid with a viscosity of 2000cP. This resinous material was heated to 120°C in the same manner as in Example 1.
After applying it on a copper wire with a diameter of 1 mm, apply it to 400
The curability of the coating film was examined by heating at ℃ for 2 minutes. The gel fraction of the obtained cured film was 94%. The properties of the obtained cured film are shown in Table 1. Example 5 Example 1 except that a mixture of 164 parts of nadic anhydride and 75 parts of glycine was used in place of N-carboxymethyl nadzikuimide in Example 1.
The reaction was carried out in the same manner as above to obtain a resinous substance. The amount of water distilled out in this case was 36 parts. The resulting resinous material had the same viscosity and the same infrared absorption spectrum as the resinous material of Example 1. The resinous material obtained in Example 5 was evaluated in the same manner as in Example 2. The results are shown in Table 1.

[Table] However, the test method was conducted in accordance with the method specified in JIS C 3210. These examples show that the cured resinous material obtained by the method of the present invention has excellent properties. Example 6 Synthesized from dimethyl terephthalate, dimethyl isophthalate, glycerin and ethylene glycol, the ratio of p-phenylene group/m-phenylene group is 9/1, the number of glycerin residues to the total dicarboxylic acid is 20%, Excess amount of polyol component is 7%
A resinous material was obtained in the same manner as in Example 1 from 591 parts of ester oligomer, 220 parts of N-carboxymethylnadic imide, 4 parts of tetraisopropoxy titanium, and 100 parts of xylene. This resinous substance was solid at room temperature, but softened by heating, becoming a liquid with a viscosity of approximately 2000 cP at 150°C. 100 parts of this resinous substance and 1 part of benzoin isobutyl ether were mixed uniformly at 150°C, and the mixture was mixed to a thickness of 0.2
After coating to form a 50μ thick film on a stainless steel plate of mm, apply it to the surface of this resin coating layer.
Irradiation was performed for 120 seconds from a distance of 25 cm using a 2KW high-pressure mercury lamp. The gel fraction of this film is 80%, and the temperature is 250°C.
No softening of the film was observed even after heating. However, when this stainless steel plate was bent, cracks appeared in the coating. Next, the irradiated coated stainless steel plate was heated to 250°C.
A uniform cured film was obtained by placing the sample in a hot air constant temperature bath adjusted to 5 minutes and performing heat treatment for 5 minutes. The cure of this film was 6 hours, and the temperature was raised at 10℃/min.
The temperature giving % weight loss was 340°C. When this coated stainless steel plate was bent at 180°C with the coated side facing out, no cracks were found in the coat. The above examples show the characteristics when the curable composition obtained by the method of the present invention is used as an insulating varnish for electric wires. The compositions have also been shown to be useful for other applications.

Claims (1)

[Scope of Claims] 1 (a) The following general formula: A(OH) _n () (A in the formula represents a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid or a derivative thereof, and the dicarboxylic acid component An ester oligomer containing 10 mol% or more of a trivalent or higher polyol relative to the dicarboxylic acid component, synthesized from a polyol component mainly composed of an aliphatic polyol, and in which the excess amount of the polyol component with respect to the dicarboxylic acid component is 35 mol% or less is an m-valent residue, where m is 2 or more determined by the ratio of the number of trivalent or higher polyol residues and the number of all polyol residues to the number of carboxylic acid residues in the ester oligomer.
Indicates a number less than or equal to 23. ) and (b) the following general formula: 1 mole of imidocarboxylic acid represented by (n in the formula is an integer of 1 or 2) (where 1 is 2
The above indicates the number satisfying m/2lm); or the following general formula: 3,6-endomethylene-1,
1 mol of 2,3,6-tetrahydro-cis-phthalic anhydride (where l is the same as above) and the following general formula: NH ₂ (CH ₂ ) _o COOH () (wherein n indicates the same as above)
A method for producing a curable composition that is cured by ultraviolet rays or heat, the method comprising reacting 1 mol of an aminocarboxylic acid represented by (where 1 is the same as above).